
DIY			Audio			Kits			www.diy-audio-kits.com

DIY Audio Kits and Projects

Novo Headphone Amp Kit

Genuine Graham Slee?

...join our COMMUNITY to ensure you always get the genuine Graham Slee - nothing else sounds the same!

With PayPal you can pay by Bank Transfer, from your PayPal balance, or by a Credit or Debit card

Headphone Amplifier Kit: The Novo Headphone Amplifier in Kit Form

Few kits are this good!

Build your own kit version of the group test winning Graham Slee Novo Headphone Amplifier which was awarded 5 stars in January 2009's What Hi-Fi Magazine and group test winner in April 2009 beating rivals: the Creek OBH-21SE, Lehmann Rhinelander and Pro-ject Headbox SEII.

Buy Online Now?

Referring to the ready made Novo, What Hi-Fi April 2009 said...

"The Novo is an involving and addictive listen"

The www.diy-audio-kits.com Novo headphone amplifier is identical in every respect to the commercial Graham Slee Novo version apart from the case graphics.

Options

Complete Kit: £120.00 + shipping + VAT

PCB Assembly + Case Kit DIY Novo headphone amplifier kit options without power supply: £112.00 + shipping + VAT

PCB Assembly Kit: £76.00 + shipping + VAT

All above kits supplied with Handbook

VAT not charged outside EEC (EU)

Please read "please note" below (click here) prior to purchase of PCB Assembly + Case Kit or Complete Kit

Buy Online Now?

A "Flexible Headphone Amp Kit"

The Novo Headphone Amplifier Kit is available in 3 options:

1... A Complete Kit: PCB Assembly Kit; Case Kit and Basic SM-PS Power Supply - the 3 packs featured above complete with the Handbook

2... PCB Assembly and Case Kits - the first two packs featured above complete with the Handbook

3... PCB Assembly Kit only - the first pack featured above complete with the Handbook

Most people will choose the convenience of being able to construct an identical (apart from panel graphics) copy of the Graham Slee Projects Novo Headphone Amplifier and go for the Complete Kit.

The power supply expert may well choose option 2 - the finished kit will then take on the characteristic of the power supply.

Option 3 is the ideal choice for the highly experienced constructor who's good at making his own enclosures - the connectors, controls and the grounding point will need to be extended off the board.

Buy Online Now?

Novo Headphone Amplifier Kit Handbook

Novo headphone amplifier kit instructions and schematic A 20 page comprehensive handbook is supplied with the Complete kit and PCB Assembly kit options.

A concise "How it Works" section explains in plain universal engineering language exactly how the circuit works.

Novo headphone amplifier kit instructions and PCB legend A fold-out circuit diagram at the rear of the book makes the explanation easy to follow, and for budding analogue designers it's excellent educational material too!

With the assistance of the fold-out large scale colour photograph the PCB assembly instructions are easy to follow.

Buy Online Now?

Novo Headphone Amplifier Specification

(Measured into 32 Ohm load except where stated)

Rated Output: 150mW RMS (40mW RMS into 600 Ohms)

Distortion (THD plus noise)
At rated (max.) output: 0.03%
At volume control mid-point: 0.01%

Input Impedance: greater than 38 kilo Ohms

Recommended input range: 200mV - 1V RMS (2.8V p-p)

Frequency Response:
At maximum output: 20 Hz - 70k Hz (-3dB points)
At volume control mid-point: 20 Hz - 50k Hz (-3dB points)

Channel Balance: 0.5dB typical

Hum & Noise:
"A-curve" weighted: -90dB
CCIR quasi-peak 20Hz-20kHz: -84dB

Stereo Crosstalk: -51dB

Size (in enclosure): L. 10.5 W. 10.5 H. 5 (cm) approx. excluding controls and connectors

Warning: Headphones can cause hearing damage if operated too loud!

Buy Online Now?

Novo headphone amplifier DIY kit in construction

Please Note: The case extrusions nearly always have a slight curvature due to the cooling metal emerging from the extrusion die. Production units are just the same. Please do not attempt straighten the extrusions - they will fit together OK and look right when fully assembled. An attempt to straighten them almost invariably will lead to disaster and be revealed in stress marks in the anodic finish. We can supply replacement extrusions at a cost.

Buy Online Now?

Graham Slee's First Audio Kit...

In actual fact the above statement is not entirely true: my first ever audio kit was back in the late 1970's - 1979 to be precise. It was a kit for a 50 watt transistor power amp that sold in just one shop in an English town called Worksop. By all accounts it was a well received kit that sounded quite good in its day. The Novo headphone amplifier has quite a lot in common with that early power amplifier kit: it shares the same basic configuration of bipolar transistors but with an output for headphones that's suitably a fraction of its power.

The information technology age has brought a tremendous amount of information to the DIY audio researcher's fingertips, and it's worth noting that unbeknown to me at the time a similar configuration was used in some of the Leak power amplifiers, whom I also believe did kits? The configuration was also used by "Elektor" magazine in its "Preco" and "Preconosant" preamplifier circuits because of its excellent performance in the days just prior to the commercial public availability of the first audio-quality operational amplifiers: the NE5534 (single) and NE5532 (dual) op-amps.

The op-amp has, it seems, made its mark on do it yourself discrete bipolar transistor design: today all we seem to see is differential inputs whether we need them or not. The fact is we don't always need a differential input to make good audio: differential inputs are a must where balanced inputs are required and often to force a DC coupled amp in preventing DC offsets appearing on its output, but high performance audio isn't entirely dependent on them. The bipolar transistor configuration used in the Novo headphone amplifier kit is more akin to what is now known in op-amp circles as "current feedback" - a phrase which suggests something highly innovative? It would appear not - perhaps it's that old "devil" known as the marketing trick? Most op-amps use just two stages of voltage amplification, and so it is with the Novo headphone amplifier - nothing much changes.

The IT revolution has also helped burst many myths: I remember the Hi-Fi magazines reporting Meridian's innovative power amplifier breakthrough of placing the output fuse in the negative feedback path thus removing the distortion it caused - but Leak were already doing the same thing by placing their output capacitor within the negative feedback loop in the days when transistor symbols were still being drawn as if a variation on the valve - and that's when Germanium transistors were still around! Well, not only does the Novo headphone amplifier capitalise on this so-called "innovation", but it also uses it to cancel a good part of its output resistance, as well as quite a lot of headphone impedance non-linearity - and to be brutally honest, it's something electronics engineers have been doing all-along, but as far as I can tell this is the first time in a headphone amplifier.

To conclude this rather lengthy introduction, the "Novo configuration" came about in the days before spice modelling, as did many other bipolar transistor configurations, but when simulated in spice the Novo's open loop gain bandwidth product is on par with the NE5532 op-amp at 10Mhz, but the Novo is driving down to 32 Ohms while the NE5532 is at 600 Ohms - progress? I hasten to add that I'm actually a "fan" of the NE5532.

Graham Slee Projects Limited
DIY AUDIO KITS Division
1 Monks Way, Monk Bretton, Barnsley, South Yorkshire, England, S71 2JD

Tel/AM +44[0]1226 244908 | +44[0]7961 322865

(I'm closed Saturdays...)

email: gsp.ltd @ gspaudio. co. uk